# We don't understand 230 mpg, but we are anxiously awaiting a good explanation

(August 2009) It's early yet. Ample time for explaining how the Chevrolet Volt, a sophisticated plug-in hybrid that will supposedly be able to travel 40 miles on its batteries alone before needing help from a gas engine — or some type of additional propulsion — will achieve 230 miles per gallon.

We don't understand how the 230 mpg has been derived. And so far no auto guru, writer or industry expert has offered any kind of explanation. Perhaps it will be some EPA hocus-pocus.

General Motors says it will take somewhere around three bucks worth of power to completely recharge the batteries. That's just under a gallon at today's prices. So how long will the Volt run before needing a complete recharge? Let's say for the sake of argument, after 40 miles of electric-motor-only driving, the Volt batteries need a half charge, say $1.50 worth of electricity.

If gas is selling for $3 a gallon that is equivalent to a half gallon of gas. In our mathematically challenged mind, that means the Volt gets the equivalent of 80 miles to the gallon, far short of the 230 advertised. If you drive the advertised 300 mile-range the Volt is expected to offer, the gas engine — which wasn't available in test mules driven this week at the GM proving grounds so we don't know how big or thirsty it will be — will surely be working during much of that trip. Common sense says it will devour at least one gallon of gas for every hundred miles.

So that would be three gallons plus the gallon equivalent to completely recharge the batteries. Let's put our elementary math skills back to work — 4 gallons divided into 300 miles yields 75 miles to the gallon. That's impressive, but again, far from 230.

It seems to us you have to measure the cost of electricity in terms of the cost of gas to have an apples-to-apples comparison.

There must be a logical explanation for 230. Right?

We are anxiously awaiting to be educated.

— Jim Meachen